Method for making a container comprising an outer skeleton and an inner layer of thermoplastic material, related container and paper-industry article used in the method

Abstract

A paper-industry article for making an outer skeleton ( 3 ) of a container ( 2 ) which also includes an inner layer ( 9 ) of thermoplastic material and which has a bottom wall ( 6 ), a plurality of lateral walls ( 5 ) and an annular perimetric flange ( 4 ), the outer skeleton ( 3 ) extending at the perimetric flange ( 4 ), at the lateral walls ( 5 ), at the bottom wall ( 6 ), wherein the paper-industry article ( 1 ) includes a continuous annular frame ( 7 ) intended to constitute the outer skeleton ( 3 ) of the container ( 2 ) at the perimetric flange ( 4 ) of the container ( 2 ), and a plurality of wings ( 10 ) which extend starting from the continuous annular frame ( 7 ), each of the wings ( 10 ) being intended to constitute the outer skeleton ( 3 ) at one of the lateral walls ( 5 ) of the container ( 2 ), and at least one of the wings ( 10 ) also being intended to constitute the outer skeleton ( 3 ) also at the bottom wall ( 6 ) of the container ( 2 ).

The invention claimed is: 
     
       1. A paper-industry article for making an outer skeleton ( 3 ) to be coupled to an inner layer ( 9 ) of thermoplastic material for making a container ( 2 ), wherein the paper-industry article ( 1 ) is obtained from the transformation of paper or cardboard into a product, wherein the container ( 2 ) comprises a bottom wall ( 6 ), a plurality of lateral walls ( 5 ) which are connected at the bottom to the bottom wall ( 6 ), and an annular perimetric flange ( 4 ) which extends outward from an upper edge of the lateral walls ( 5 ), in the container ( 2 ) the outer skeleton ( 3 ) being configured to be arranged at the perimetric flange ( 4 ), at the lateral walls ( 5 ) and at the bottom wall ( 6 ), the paper-industry article ( 1 ) comprising:
 a continuous annular frame ( 7 ) configured to constitute the outer skeleton ( 3 ) of the container ( 2 ) at the perimetric flange ( 4 ) of the container ( 2 ); and 
 a plurality of wings ( 10 ) which extend starting from the continuous annular frame ( 7 ), each of the wings ( 10 ) being configured to constitute the outer skeleton ( 3 ) at one of the lateral walls ( 5 ) of the container ( 2 ), and at least one of the wings ( 10 ) also being configured to constitute the outer skeleton ( 3 ) also at the bottom wall ( 6 ) of the container ( 2 ). 
 
     
     
       2. The paper-industry article according to  claim 1  wherein the paper-industry article ( 1 ) extends mainly parallel to a main plane of extension of the continuous annular frame ( 7 ). 
     
     
       3. The paper-industry article according to  claim 2  wherein the continuous annular frame ( 7 ) is at least partly superposed on one or more of said wings ( 10 ) and/or wherein at least some of said wings ( 10 ) are partly superposed on each other. 
     
     
       4. The paper-industry article according to  claim 2  wherein the paper-industry article ( 1 ), observed perpendicularly to the main plane of extension, has an outer profile defined by an outer portion of the continuous annular frame ( 7 ). 
     
     
       5. The paper-industry article according to  claim 4  wherein said wings ( 10 ) extend at least partly from the continuous annular frame ( 7 ) inward and wherein each wing ( 10 ) is at least partly superposed on at least one of the other wings ( 10 ). 
     
     
       6. The paper-industry article according to  claim 1  wherein the continuous annular frame ( 7 ) has a continuous upper surface ( 8 ) suitable for in use being coupled to the inner layer ( 9 ) of thermoplastic material of the container ( 2 ). 
     
     
       7. The paper-industry article according to  claim 1  comprising at least one main sheet ( 13 ) which has an annular portion ( 15 ) which defines at least one continuous upper surface ( 8 ) of the continuous annular frame ( 7 ), wherein the annular portion ( 15 ) is also at least partly superposed on one or more of said wings ( 10 ). 
     
     
       8. The paper-industry article according to  claim 4  wherein the continuous annular frame ( 7 ) has a continuous upper surface ( 8 ) suitable for in use being coupled to the inner layer ( 9 ) of thermoplastic material of the container ( 2 ). 
     
     
       9. The paper-industry article according to  claim 4  comprising at least one main sheet ( 13 ) which has an annular portion ( 15 ) which defines at least one continuous upper surface ( 8 ) of the continuous annular frame ( 7 ), wherein the annular portion ( 15 ) is also at least partly superposed on one or more of said wings ( 10 ). 
     
     
       10. The paper-industry article according to  claim 2  wherein said continuous annular frame ( 7 ) has an inner edge ( 16 ) and an outer edge ( 17 ), wherein the continuous annular frame ( 7 ) and at least one of said wings ( 10 ) are constituted of a single sheet of material, and wherein, alternatively, if observed perpendicularly to the main plane of extension:
 said at least one of said wings ( 10 ) extends inside the continuous annular frame ( 7 ) starting from the inner edge ( 16 ) of the continuous annular frame ( 7 ); or 
 said at least one of said wings ( 10 ) extends starting from the outer edge ( 17 ) of the continuous annular frame ( 7 ), is folded under the continuous annular frame ( 7 ) around the outer edge ( 17 ) and the rest of it extends inside the continuous annular frame ( 7 ). 
 
     
     
       11. The paper-industry article according to  claim 1  comprising a number of wings ( 10 ) equal to a number of lateral walls ( 5 ) of the container ( 2 ), and/or wherein each wing ( 10 ) comprises a main portion ( 11 ) shaped in such a way as to completely define the outer skeleton ( 3 ) at one of the lateral walls ( 5 ), and/or wherein each wing ( 10 ) has an additional portion ( 12 ) shaped in such a way as to partly define the outer skeleton ( 3 ) at the bottom wall ( 6 ). 
     
     
       12. The paper-industry article according to  claim 1  wherein the paper-industry article ( 1 ) is made cardboard- or paperboard-based, and/or wherein the paper-industry article ( 1 ) has fold lines at connection zones between its operating portions intended to constitute the outer skeleton ( 3 ) respectively at the perimetric flange ( 4 ), at each of the lateral walls ( 5 ) and at the bottom wall ( 6 ), and/or wherein the paper-industry article ( 1 ) has one or more holes and/or one or more slits and/or one or more outlines, which are suitable for in use allowing the passage of air between an upper part of it and a lower part. 
     
     
       13. The paper-industry article according to  claim 4  comprising a number of wings ( 10 ) equal to a number of lateral walls ( 5 ) of the container ( 2 ), and/or wherein each wing ( 10 ) comprises a main portion ( 11 ) shaped in such a way as to completely define the outer skeleton ( 3 ) at one of the lateral walls ( 5 ), and/or wherein each wing ( 10 ) has an additional portion ( 12 ) shaped in such a way as to partly define the outer skeleton ( 3 ) at the bottom wall ( 6 ). 
     
     
       14. The paper-industry article according to  claim 4  wherein the paper-industry article ( 1 ) is made cardboard- or paperboard-based, and/or wherein the paper-industry article ( 1 ) has fold lines at connection zones between its operating portions intended to constitute the outer skeleton ( 3 ) respectively at the perimetric flange ( 4 ), at each of the lateral walls ( 5 ) and at the bottom wall ( 6 ), and/or wherein the paper-industry article ( 1 ) has one or more holes and/or one or more slits and/or one or more outlines, which are suitable for in use allowing the passage of air between an upper part of it and a lower part. 
     
     
       15. Use of a paper-industry article according to  claim 1  for making a container ( 2 ) comprising an outer skeleton ( 3 ) and an inner layer ( 9 ) of thermoplastic material coupled to the outer skeleton ( 3 ), comprising the operating steps of:
 (a) taking the paper-industry article ( 1 ); 
 (b) making the outer skeleton ( 3 ) using the paper-industry article ( 1 ); 
 (c) thermoforming the inner layer ( 9 ) of thermoplastic material directly on the outer skeleton ( 3 ), thereby fixing it to the outer skeleton. 
 
     
     
       16. The use according to  claim 15  wherein the step of making the outer skeleton ( 3 ) comprises the step of inserting the paper-industry article ( 1 ) into a female mould ( 19 ) of a thermoforming device ( 20 ), and the step of covering at least partly the lateral surfaces ( 22 ) and the bottom surface of the female mould ( 19 ) with the wings ( 10 ), and wherein the step of thermoforming the layer of thermoplastic material is carried out using the thermoforming device ( 20 ) into which the paper-industry article ( 1 ) has been inserted. 
     
     
       17. The use according to  claim 16  wherein the step of covering with the wings ( 10 ) at least partly the lateral surfaces ( 22 ) and the bottom surface of the female mould ( 19 ), comprises the step of pushing the wings ( 10 ) against the female mould ( 19 ) by inserting a male-shaped shaping unit ( 25 ) into the female mould ( 19 ).